<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            padding-left: 210px;
            padding-right: 190px;
        }

        .main {
            float: left;
            width: 100%;
            height: 300px;
            background-color: #eeeeee;
        }

        .sub {
            position: relative;
            left: -210px;
            float: left;
            width: 200px;
            height: 300px;
            margin-left: -100%;
            background-color: ccc;
        }

        .extra {
            position: relative;
            right: -190px;
            float: left;
            width: 180px;
            height: 300px;

            margin-left: -180px;
            background-color: #d3d3d3;

        }
    </style>
</head>

<body>
    <div class="container"> 
        <div class="main"></div> 
        <div class="sub"></div> 
        <div class="extra"></div> 
    </div>
</body>

</html>